Many research methods applied in molecular neuroscience require the collection of hippocampal samples, but a still poorly recognized problem is contamination with the choroid plexus during brain dissection. Because of a distinct pattern of gene expression, its inclusion in brain samples can obscure or even confound conclusions drawn from molecular studies. Therefore, we tested our dissection method designed for removal of tissue contamination using expression of the transthyretin gene (Ttr) as a marker of the choroid plexus. Additionally, we also validated dissection of the entire hippocampus into its dorsal, intermediate and ventral subdivisions using the expression of Trhr and Lct genes as molecular markers of anatomical subdivisions. The PCR analysis showed that Ttr is expressed at a residual level in hippocampal samples that display an mRNA level several hundred lower than the adjacent control tissue colocalized with the choroid plexus. This indicates that the applied method for dissecting the hippocampus from a fresh brain allows for replicable removal of the majority of choroid plexus from hippocampal samples. In turn, differences in expression of Lct and Trhr confirmed the proper dissection of dorsal, intermediate and ventral subdivisions from fresh brain tissue. Therefore, a special emphasis on the removal of tissue contamination and avoidance of tissue distortions makes our protocol especially suitable for molecular experiments performed either on the entire hippocampus or its subdivisions.

The aim of the experiment was to test the effect of an elevated level of glucocorticoids on the mouse hippocampal transcriptome after 12 h of treatment with corticosterone that was administered during an active phase of the circadian cycle. Additionally, we also tested the circadian changes in gene expression and the decay time of transcriptomic response to corticosterone. Gene expression was analyzed using microarrays. Obtained results show that transcriptomic responses to glucocorticoids are heterogeneous in terms of the decay time with some genes displaying persistent changes in expression during 9 h of rest. We have also found a considerable overlap between genes regulated by corticosterone and genes implicated previously in stress response. The examples of such genes are Acer2, Agt, Apod, Aqp4, Etnppl, Fabp7, Fam107a, Fjx1, Fmo2, Galnt15, Gjc2, Heph, Hes5, Htra1, Jdp2, Kif5a, Lfng, Lrg1, Mgp, Mt1, Pglyrp1, Pla2g3, Plin4, Pllp, Ptgds, Ptn, Slc2a1, Slco1c1, Sult1a1, Thbd and Txnip. This indicates that the applied model is a useful tool for the investigation of mechanisms underlying the stress response.

This study evaluated the impact of husbandry practices including enrichments, diet, stocking density, genotype, and outdoor access on welfare indicators in fast-growing Ross 308 and two genotypes of medium-growing Hubbard hybrids of chickens. The set of studies was designed with specific factors relevant to each genotype, with stocking density, perch enrichment and lucerne provision targeted for Ross 308 broilers and perch, outdoor access, as well as genotype (JA757 and JA787) for Hubbard chickens. Feather condition, footpad dermatitis (FPD), comb wounds, skin injuries, hock burn, lameness, dirtiness, toe damage, respiratory infections, and diarrhea were evaluated at the end of each production cycle. For Ross 308, just like for Hubbard hybrids, enrichment with perches significantly deteriorated feather condition (P = 0.03). Lucerne provision enhanced footpad health (P = 0.02) and reduced comb wounds (P = 0.03). For Hubbard hybrids, outdoor access led to a reduction in comb wounds (P = 0.04) and FPD severity (P = 0.02). Additionally, differences in plumage damage were observed between the Hubbard hybrid genotypes (P = 0.03), with less damage observed in Hubbard JA757, as compared to JA787. These findings enhance understanding of how targeted modifications in husbandry practices improve poultry welfare and provide practical guidance for optimizing broiler production systems.

The composition of genomic mediators of glucocorticoid actions in the brain remains elusive because of low-statistical-power experiments and the associated transcriptomic data with very low consistency. The problem is further exaggerated by the underrepresentation of chronic experiments and the interpretation of differentially expressed genes without understanding their contribution to the total transcriptomic activity. To fill existing gaps in knowledge, we have performed a large transcriptomic experiment, testing the effects of prolonged treatment with corticosterone on the hippocampal transcriptome (RNA sequencing). The experiment showed that prolonged treatment with corticosterone induced a set of transcriptomic effects that were replicable across treatment durations, including genes relevant for human PTSD (Opalin, Pllp, Ttyh2, Lpar1) and prolonged stress in animals (Cnp, Fam163a, Fcrls, Tmem125). Some of the affected genes are specific for oligodendrocytes, neurons, astrocytes, immune cells, the vascular system, and brain ventricles, indicating that glucocorticoids may affect all central nervous system components. The data also showed that the largest changes in expression of corticosterone-responsive genes are restricted to genes with a relatively low expression level and small contribution to the overall pool of mRNAs in the hippocampus. As a result, even a large change in the number of affected genes leads to a small change in the number of newly synthesized mRNA copies. This means, in turn, that the transcriptomic changes induced by corticosterone have low-cost effects on the brain. This specificity of transcriptomic responses also poses a challenge for the interpretation of data and constitutes a potential source of reporting bias in past studies. Therefore, there is a need for further research on products of gene expression, both at the transcriptomic and proteomic levels, during stress conditions.

This study aimed to evaluate the effects of two housing systems (free-range vs. indoor) and two slow-growing chicken genotypes (Hubbard JA 757 and JA 787) on breast meat quality traits relevant to consumer acceptance and processing. A total of 120 Hubbard broilers were divided into four groups based on genotype and housing conditions (30 birds per group). Physicochemical properties of the Pectoralis major muscle were analyzed post-slaughter (both fresh and frozen) to assess pH, color, water-holding capacity, texture, chemical composition, and incidence of muscle myopathies (Spaghetti Meat, Wooden Breast, and White Striping). Among the evaluated parameters, only the housing × genotype interaction significantly affected pH48. Housing system significantly influenced b* and C* color values (p = 0.0001), suggesting changes in meat pigmentation due to environmental conditions. JA757 birds exhibited higher thaw loss, while cooking loss was significantly affected by both genotype and housing, as well as their interaction. Texture analysis revealed that genotype significantly affected Young's Modulus at both the 0-10 % and 20-80 % ranges, while housing conditions impacted the latter. Spaghetti Meat was more prevalent in JA787 birds and those raised indoors (p = 0.0001 and p = 0.01, respectively), whereas Wooden Breast and White Striping were not significantly influenced by genotype or housing. Fat content was significantly influenced by the housing system and its interaction with genotype, while protein and moisture contents remained stable across treatments. Genotype had a stronger influence on textural attributes and myopathy incidence, while housing conditions primarily shaped pH, pigmentation, water retention, and fat content. These findings underline the importance of aligning broiler genotype with rearing environment to optimize meat quality. Free-range systems, particularly in combination with the JA757 genotype, may better suit premium markets focused on animal welfare and tenderness, while indoor systems with JA787 birds may be better adapted to processed meat production.

This study examined the influence of feeding frequency on the morphology of the reproductive tract in broiler breeder hens, with a focus on the liver, ovary, and oviduct. A total of 364 hens and 52 roosters, starting at 31 wk of age and continuing until the end of their 38th week, were divided into 13 groups with varying feeding frequencies (1, 2, or 3 times daily). Significant changes in reproductive and metabolic parameters were observed, where feeding hens twice or thrice daily resulted in significantly reduced ovary weight and follicle counts (P < 0.001), while liver weight increased (P < 0.05). These findings suggesting complex interactions between feeding practices and reproductive efficiency.